A method utilizing the binocular parallax is known as a method for allowing a user to view a video displayed on a flat-panel display as a stereoscopic video. This is a method which utilizes a fact that a user perceives the depth because the user's right and left eyes are positioned away from each other and videos in the left eye and right eye have different viewpoints.
The method utilizing the binocular parallax allows a user to perceive stereoscopy in the user's brain by displaying different videos to the user's right and left eyes. However, such stereoscopic view achieved by a method apart from reality may give the user visual fatigue or a sense of discomfort.
Thus, a stereoscopic video display apparatus is proposed which estimates the level of fatigue in visual function of the eyes due to fatigue of the eyes, and adjusts, in accordance with the estimated level of fatigue, the degree of stereoscopy (a value indicative of the degree of stereoscopy) (for example, see PTL 1).
In addition, a system is proposed which allows a user to view a 2D video while a 3D video is presented on a display screen, by the user switching, in eyeglasses for viewing a 3D video presented by the frame sequential method, a switch timing of liquid crystal shutters of the eyeglasses (for example, see PTL 2).